1. Field of the Invention
This invention relates to soil sterilization. More specifically, the invention relates to sterilizing otherwise highly fertile soil which is badly contaminated with pests which include, but are not restricted to, nematodes i.e. eel worm, and seeds.
2. Description of Related Art
Hitherto it has generally been necessary to either accept the sometimes major reduction in yield or to apply chemical pesticides. In view of the concerns expressed about the environmental and human effects of pesticides there is a considerable need for a nonchemical method of destroying soil-borne pests.
It has been known from old to sterilize mushroom beds by passing steam through perforated pipes in the beds. This method is not suitable for use in fields because of the cost of laying the pipes. Additionally, the control of temperature is very difficult. Parts of the bed will probably be heated too much and the soil structures damaged and the microbiological populations distorted too greatly. Conversely, other parts are likely to be insufficiently heated and thus not freed of infestation.
WO94/01723 published on Jan. 20, 1994 describes a straw burner. Straw is harvested, chopped, and passed to a burner. Combustion gases exiting the device may impinge on the ground. These gases may ignite dry plant material on the surface and possibly over-heat the top-most part of the soil. It is unlikely that any effect will be present lower down.